Method and apparatus for off shore drilling



lBTHOD ANDPPAR'ATUS FOR vOFF ',SHORE DRILLI'NG Filed Dec. v1o, 195e Oct. 28, 1969 w. c. GIBSON r-:TAL

Sheets-Sheet l Fass/Mktl/b/k, INVENTORS. Raymond E. Thom/250,;

0th 28, 1969 w. c. GIBSON ETAL 3,474,858

METHOD AND APPARATUS FOR OFF SHORE DRILLING Filed Dec. 10, 195e 7 sheetssheet 2j,

Wilfred C. Gibson, l Foss Mc Cfl'moc, Raymand E. Thomson, uvVENToRs.-

//omsl BY Z Of- 23 1959 w. c. GIBSON ETAL 3,474,858

METHOD AND APPARATUS FOR OFF SHORE DRILLING Filed Dec. 10, 1956 '7 Sheets-Sheet 3 Y Z i:

OSf- 28, 1969 w. c. GIBSON E11-Al. 3,474,858

METHOD AND APPARATUS FOR OFF SHORE DRILLING Filed Dec. 10. 1956 F/. /84 v 47d 'A' 2a' 28 47./ l

/lz "l /fo "6 H5 /oa W/fred CG/son, Foss 'cC/mocl', Raymond E. nan/aso, v INVENTORS.

' Afford@ v 'r sheets-sheet@ Oct. 28, 1969 w. c. GlBsoN ETALl 3,474,858

I METHQD AND APPARATUS FOR OFF SHORE DRILLING Filed Dec. l0, 1956 '7 Sheets-:Sheet .5A

Ross A. Mc C/hfocl', Raymond T/lampson,

IN V EN TORS.

METHOD AND APPARATUS FOR OFF SHOREA DRILLING v I Filed D96. 10, 1956 Oct. 28, 1969 v w. 12. GlBsr'ON ETAIT 7 Sheets-Sheet 6 JNVENToRs.

/ Home] Oct 23, 1969 y y w. c. GIBSON ETAL l 3,474,858

METHOD AND APPARATUS FR OFF SHORE DRILLING Filed Dec.. 1o, 1956 7 sheets-sheet 7 W/frec/ C Gibson, /Poss Mc C/hfoc', Raymond E. Thom/asa,

1N VEN TORS,

United States Patent O 3,474,858 METHOD AND APPARATUS FOR OFF SHORE DRILLING Wilfred C. Gibson, Fullerton, Ross A. McClintock, range, and Raymond E. Thompson, Fullerton, Calif., assignors to Shaffer Tool Works, Brea, Calif., a corporation of California Filed Dec. 10, 1956, Ser. No. 627,250 Int. Cl. EZlb 15/02, 33/16, 43/01 U.S. Cl. 166-.5

This invention relates generally to the drilling of wells and relates more particularly to apparatus and Imethod for offshore drilling of wells. E

While the invention has particular utility in connection with offshore drilling of oil wells and the like, and is herein shown and described as embodied in connection therewith, it is to be understood that its utility is not limited thereto.

Where the water is shallow, the problems of offshore or underwater drilling are not diicult of solution. However, there are many dillicult problems involved in drilling in deep water and in certain localities such as the Pacific Coast, for example, the waters are relatively deep even a short distance from shore.

When the drilling is in such relatively deep water, a floating platform is used and comprises a specially equipped boat or barge which must be anchored as securely as possible, but even though the boat is securely anchored, there will be a certain amount of movement thereof due to wave and tidal action and there must be means for compensating for such movement throughout the entire drilling operation. Additional problems are involved in the locating of the wellhead and blowout preventer equipment which should be mounted as close to the ocean floor as possible.

It is, therefore, an object of the present invention to provide means and method for solving the above problems.

It is another object of the invention to provide means located close-to the ocean floor for remotely connecting and disconnecting the various equipment to the casing.

It is still another object of the invention to provide means for compensating for wave motion and to manipulate the tools used to release the safety joints.

It is a further object of the invention to provide means and method for providing a continuous connection between the casing and the lbarge for further drilling operations.

It is .a still further object of the invention to provide means and method for lowering and connecting various tools to the mandrel of the casing.

It is another object of the invention to provide means and method for releasing said tools and raising same when it is desired to do so.

When drilling oil wells with rotary drilling equipment a drilling fluid is used `and is circulated through the drill string and then pumped to screening and storage tanks. In underwater drilling operations certain problems are encountered in the handling of the drilling lluid and it is still another object of the invention to provide means for the proper handling of the drilling fluid.

It is a further object of the invention to provide means for handling the drilling uid so that such fluid will not escape into the water and contaminate same.

It is still another object of the invention to provide means and method for removing various equipment when the drilling has been completed.

The characteristics and advantages of the invention are further sufficiently referred to in connection with the Claims 3,474,858 Patented Oct. 28, 1969 vICC following detailed description of the accompanying drawings which represent a preferred embodiment of the method and apparatus or means. After considering this example, skilled persons will understand that many variations may be made without departing from the principles disclosed, and we contemplate the employment of any structures, arrange-ments or modes of operation that are properly within the scope of the appended claims.

Referring to the drawings:

FIG. 1 is a perspective undersea View showing equipment embodying the present invention;

FIG. 2 is an enlarged side view of the upper end of the casing whichhas been drilled into place and with the parts of the safety joints connected together;

FIG. 3 is an enlarged side elevation of the upper end of the landed casings with the cable anchor and weight housing attached and the upper portion of the safety joint detached from the mandrel secured to the upper end of said casing;

FIG. 4 is an enlarged elevational view showing the preventer land drilling head equipment positioned for attachment to the mandrel at the upper end of the landed casing;

FIG. 5 is an enlarged elevational view of wellhead and preventer equipment attached to the landed casing;

FIG. 6 is an enlarged elevational view showing the anchor removed from the landed casing;

FIG. 7 is a diagrammatic side view of the equipment for maintaining the guide cables under tension;

` FIG.v 8 is a diagrammatic plan view of a portion of the cable tensioning equipment;

FIG. 9 is a side View of the gate lifting sub and safety joint release tool operatively connected to a bumper sub and positioned relative to supported wellhead `and pre- Venter equipment;

FIG. 10 is a diagrammatic side view of the bumper sub release tool;

FIG. 11 is a side View of a guide rod;

FIG. 12 is an enlarged side view partially in section, showing the cement follower plug in position between the upper end of the top sub of the safety release joint and the crossover sub;

FIG. 13 is an enlarged sectional view taken on line 13-13 of FIG. 12 to particularly show the upper end of the follower plug;

FIG. 14 is a side view of the submarine drilling head with portions broken away;

FIG. 15 is an enlarged longitudinal center section taken on lines 15-15 of FIG. 2; and

FIG. 16 is a side View, partly in section, of an alternative type of submarine drilling head.

Referring to FIG. l, there is shown a boat or barge, indicated generally at 20, which is anchored at a preselected location. The anchoring means includes a plurality of buoys 21 attached to cables 22 from the boat or barge. There are two buoys at each end of the boat and said buoys are spaced laterally apart relative to the length of the boat or barge. From the buoys 21 there are cables 23 leading to suitable anchors, not shown in view of the fact that any well known type of anchor may be used.

The boat is provided with an opening 25 therethrough and `a mast 26 is operably dispo-sed with respect to the opening 25. Various required equipment is installed on the boat 20 and includes means for maintaining guide cables 28 under tension.

The lower ends of said cables are secured to an anchor, indicated generally at 30, removably secured to a mandrel, indicated generally at 31, of a safety release joint having a barrel, indicated generally at 32, detachably secured to said mandrel as will be described more particularly hereinafter. The upper ends of the cables 28 are wound on respective sand reel drums 34. Each dru-m has a shaft 35 mounted in suitable bearings 36, one end of said shaft having a sheave 37 connected -by belt 38 with a sheave 39 of a torque converter driven by a power unit, said converter and power unit being indicated generally at 40. Each of the cables 28 pass from the sand reel drums over a sheave 42 then under a sheave 43 and thence over a sheave 44 and then downwardly through the opening 25 in the boat.

Above the barrel unit 32 of the safety joint is a double cellar control gate or blowout preventer, indicated generally at 45, and above said blowout preventer is a preventer 46. Above the preventer 46 is a submarine drilling head, indicated generally at 47.

The drill string is indicated generally at 50 and passes through the head 47 `and preventers 46 and 45 as shown in FIG. 4 The upper end of the drill string is connected in the usual manner to equipment of well known character for rotating the drill string and otherwise manipulating same. Pressure for operating the preventers and/or other equipment below the boat or barge is supplied through various conduits secured together to form a sheaf, indicated generally at 52, which extends from suitable equipment on the boat downwardly to the door of the ocean or other body of water, said botto-m being indicated at 33. The sheaf rests on said bottom 33 to prevent it from being whipped about by the currents.

Drilling fluid of any suitable type is circulated through the equipment used for rotary drilling and the circulatory system thereof will be described more particularly hereinafter.

Preparatory to the drilling of a well according to the process or method of the present invention, an equipped ship or barge is floated to the preselected location where the drilling is to be done. The ship is then suitably anchored by any well known arrangement such as, for example, that described hereinabove.

The first phase of the underwater drilling operation comprises the setting of surface pipe so that mud circulation can be established and blowout prevention equipment installed.

Sufficient casing to drill through ocean bottom sediments into solid formations 33a is assembled in the usual operating equipment on the boat. At the bottom of the casing is a bit similar to a washover shoe of known character and a drillable bar, or core wiper is provided across the face of the bit to prevent a core from forming in the casing. A conventional float shoe may also be inserted in the string above the bottom joint. The bit, core wiper and float shoe may be of standard construction as used in the ordinary drilling procedures, as for example, the equipment and procedures outlined in the book, Petroleum Production Engineering, Third edition, by Lester Charles Uren, published by McGraw-Hill Book Company, Inc., 1946.

When the desired length of casing has been assembled, a casing safety joint of the correct size is assembled at the upper end of said assembled casing. By way of example, safety joints such as disclosed in the Kenneth E. Waggener application for Torque Releasing, Safety Joint for Well Tool Strings, Ser. No. 390,321, tiled November 5, 1953, now US. Patent No. 2,893,694, may -be used. The safety release joint provides means for remotely disconnecting or connecting the casing during later operations.

Above the safety joint is a crossover sub 60, said crossover sub being connected at its lower end to the upper end of the barrel unit 32 of the safety jo'mt, said crossover sub tapering to a reduced diameter portion 61 which is connected to the adjacent drill tubing 62. This arrangement provides means for reducing to the drill tubing size.

At the upper end of the barrel unit of the safety joint,

the device is provided with the usual internally threaded tapering socket 64 and at the lower, smaller diameter end of the socket 64 there is a shoulder 65 on which is seated a ring 66 which is held in position by the lower, smaller diameter end of the pin 67 of the crossover sub 60. Ring 66 supports a cement follower plug, indicated generally at 70. The cement follower plug comprises a tube 71 having a plurality of wiping elements 72 of suitable resilient material such as a synthetic rubber or the like and said elements are secured to the tubular body 71 in longitudinally spaced relationship thereof by any suitable means such as a bonding process of well known character. The tubular body 71 of the follower plug is axially disposed and the upper end thereof is provided with radial openings arranged to register with radial openings provided in the ring 66 and in which are disposed shear pins 74. The inner ends of the shear pins do not extend into the central passage 75 of the tubular body 71, said passage 75 allows circulation of the drilling fluid during drilling-in operations.

The part of the drill string indicated at `62 comprises a drilling bumper sub, a device well known in the well drilling art, the upper end of which has attached thereto drill tubing 80. The functions of drilling bumper sub 62 are to provide compensation for wave motion and to manipulate the tools used to release the safety joint as will be described more fully hereinafter. Where necessary, additional bumper subs may be used in the string above the bumper sub 62 where wave motion is greater than the capacity of a single bumper sub unit,

A groove 82, FIG, l, is provided adjacent the lower end of the mandrel to accommodate a depth control member, indicated generally at 83, which comprises a pair of semicircular plates 84 which are secured together by rivets 85 or by any other suitable means Such as welding or the like. The element 83 functions as a stop for the casing after sufficient hole has been cut to bring said element into contact with the ocean floor.

The mandrel 31 is connected to the upper end of the casing string 88. When the casing has been drilled into place, cementing operations are started. These are carried out along conventional lines, that is, the cement is pumped down the drill string until the necessary volume has been inserted, it being noted that the cement passes through the tubular body 71 of the cement follower plug. Above the kelly there is a side door kelly cock in the drill string which permits access to the mud circulating system without danger of backow. After the mud has been added, the kelly cock is opened and a ball is inserted therein. The ball is pumped down the string until it seats on the upper end of the cement follower plug -body 71, said ball being indicated in FIG. 12 at 92. Seating of the ball closes the passage 75 through the cement follower plug so that pump pressure above said ball and plug increases until the pi'ns 74 are sheared. Thereafter, the pressure above said plug and ball force said plug down the casing until it seats in the float shoe in a manner well known in the drilling art. A second increase in mud pump pressure will indicate that the plug has reached this position. The cement, which has gone down through the string and casing and up about the outside of the casing to the approximate level of the ocean floor, is allowed to set the usual period necessary to insure good bond and strength.

After the cement has hardened, and before releasing the safety joint and continuing drilling operation, a continuous connection between the casing and barge is effected. The means for providing such connection comprises the cables 28 and the weight housing or anchor 30.

Weight housing or anchor 30 comprises a tubular -body of such internal diameter as to readily accommodate the barrel unit 32 of the safety joint and to slide thereover. At the upper end of said tubular body there is an outwardly flaring funnel shaped member 101 which may be integral with the body 100 or which may be a separate piece secured to said body by Welding, brazing or by any other suitable means. Concentrically disposed about said body 100 is a tubular reinforcing support 102, the lower end of said support being in substantially the same plane as the lower end of said body, the upper end of said support contacting the underside of the funnel 101 and being secured thereto by any suitable means such as brazing, Welding or the like. At the upper end of the Weight housing or anchor 30 are a pair of oppositely extending radial arms 104 secured at their inner ends to the funnel portion 101 of said anchor and having at their respective outer ends a pair of ears 105 secured thereto and spaced apart longitudinally with respect to their respective arms. Pivot pins 105 are supported by the respective pairs of ears at the ends of said arms and cable clamps 106 at the respective ends of said cables 28 are pivotally attached to said pins 105. Adjacent the lower end of the tubular body there is a longitudinally extending notch 108 at the side of which are outwardly extending ears 109. Ears 109 carry a pivot pin 110 on which is pivotally mounted a latch member, indicated generally at 111. Latch member 111 has an upwardly extending arm 112 and at the lower end of said member there is an inwardly projecting boss or detent 114 which extends through the slot 108 and is adapted to enter an external annular groove 115 in the mandrel 31 above the plates 83, A Wire spring or other suitable type of spring 116 coiled about the pivot pin 110 is provided, the ends of said spring reacting between the tubular body 100 and the member 112 to urge said detent or boss 114 into said groove 115. In order to facilitate assembly of the anchor about the drill string, said anchor comprises a .pair of complementary parts or halves and the parts are `divided longitudinally at diametrically opposite sides which are at substantially right angles to the arms 104. The line of division is thus shown in FIG. 5 at 120 and there are outwardly extending flanges 121 along said lines of division. The flanges 121 are provided with registering openings for reception of screws 122. Thus, when the anchor of weight housing is attached the two parts are put together about the drill string and the screws 122 are inserted and tightened. The anchor is then lowered until the latch 111 engages the groove 115 t0 thereby lock said anchor securely to the mandrel.

As above pointed out, the upper ends of said cables are wound on the sand reel drums which are connected to torque converters. With this arrangement the cables may be maintained under proper tension but will wind and unwind on said sand reel drums with the motion created by the waves and tide. There are, of course, other methods for maintaining tension on said cables. The cables thus provide a connection between the casing and the barge or boat and also serve as guides to locate equipment on the wellhead as said equipment is lowered into place.

After the casing has been drilled in, the cementing operation completed and the anchor 30 attached, the barrel unit of the safety joint is released. Where the safety joint used is similar to that disclosed in United States Patent No. 2,893,694 to Waggener, a releasing tool, indicated generally at 130, FIGS. 3 and l0, may be utilized to effectuate a disconnection. This tool comprises an elongated bar 131 having an enlarged head 132 at its upper end and a pair of prongs 133 at its lower end. Prongs 133 are pivotally connected at their lower ends to said bar and are urged outwardly 'by means of springs or the like. Similar kinds of releasing tools are well known in the drilling art and the specific form illustrated is not to be considered part of this invention. It is to be understood, of course, that there may be other means for effecting release of a barrel unit from its mandrel, the form of the releasing tool depending upon the safety joint construction.

To effect release of the Waggener type safety joint the tool 130 is inserted in the bore of the drill tubing at the derrick floor. The bar falls down the bore in the tubing until the head 132 seats on shoulder 62a in the top of the drilling bumper sub 62 as shown in FIG. 15. The prongs or fingers 133 engage a groove in the locking sleeve of the barrel unit of the safety joint when the drilling bumper sub is closed or substantially closed. Upward movement of the drilling string will then open the drilling bumper sub and move the locking sleeve in the safety joint to a releasing position. Continued upward pull on the safety joint barrel unit causes same to disconnect from the mandrel. When the barrel unit has been separated from the mandrel, as shown in FIG. 3, the drilling string can then be raised to the surface, and preparations for installing the preventer started.

In preparation for the drilling of the main hole, the subsea control unit is made up, this unit comprising the drilling head 47, a spool 135 with a side outlet 136 (FIG. 5) to which a return mud line 137 is attached, the preventer 46, and the double hydraulic preventer 45. A safety release barrel unit 32 is attached to the lower end of the `dou-ble preventer 45 as best shown in FIGS. 1, 4 and 5.

The drilling head 47 may be of any well known type which provides a seal with the drilling string so that fluid cannot escape about said string. Thus, the fluid circulated during the drilling operations and pumped down the drill string and then upwardly about said string cannot escape past the head 47 and is forced to leave by way of the side outlet 136 of the. spool 135 and thence upward to the boat or barge 'by Way of the iiow line 137 which leads to and discharges into a tank 140, FIG. l. A plurality of tanks may be used and motor driven rapid mixers of known type provide the means for mixing the uid in said tank. The mixed fluid is pumped from the tank or tanks and -into the drill string thus maintaining circulation through the equipment during drilling operations.

Preventer 46 is of a type adapted to pack off various types of equipment disposed therein. This preventer is adapted to pack off tools joints, pipe of different sizes, and the open hole. Bag types of preventers, known in the art, will perform these functions.

The double hydraulic control gate preventer 45 includes a pair of opposed complete shutoff ram blocks 142, only one of said blocks being shown in FIG. 4. Each of these blocks is actuated hydraulically by means of a piston 143 operably disposed in a cylinder 144 and connected with said ramr blocks by means of a connecting rod 145. Hydraulic fluid under pressure is admitted to one side or the other of the pistons 143 so as to cause same to move the blocks 142 toward each other or away from each other to close or open the passage through the preventer when no equipment or pipe is disposed in said passage. Above the complete shutoff blocks 142 are a pair of oppositely arranged ram blocks 147, said ram blocks 147 are provided with semicircular recesses in their adjacent faces to accommodate a pipe or the like disposed in the said passage of the preventer 45. The blocks 147 are movable toward and away from each other by means of respective pistons 148 operably disposed in cylinders 149 and connected to the respective block 147 by means of connecting rods 150. Fluid or hydraulic pressure is admitted to one side or the other of pistons 148 to effect movement of the blocks 147 t0- ward and away from each other to engage or disengage a pipe disposed in the passage of said preventers. Hydraulic pressure is transmitted from suitable pressure creating equipment, not shown, of well known pipe located on the barge by way of the conduit of the sheave 52. Valves, also not shown, of any 'well known type are used to control the pressure from said pressure creating equipment to the particular side of the pistons of the respective ram blocks. In FIG. 1 the conduits 154 are connected with the blowout preventer 45.

Conduits are connected to the preventer 46 to supply pressure for operating said preventer between the open position and a closed or engaging position.

A typical drilling head 47, as shown in FIG. 14, is provided with a sealing sleeve which is stripped over the string before the bit is attached thereto and is carried down with the string until it enters the funnel shaped end 47a of the casing 47h. The sleeve is held in sealing engagement with the drill string by means of segments 162, which are urged inwardly by pistons 163 on connecting rods 165 connected with said segments. The pistons 163 are supplied With operating pressure by means of conduits 168, the pressure to which is also controlled by valves on the boat. When drilling operations are under way the sleeve 160, which is of any suitable material such as a synthetic rubber that will resist the action of fluid and the like to which it is exposed is locked in position by Said segments 162. However, when it is desired to remove the string, the segments 162 are released by pressure applied to the other side of piston 163 to permit removal of the bit from the equipment as said bit is too large to pass through the sleeve and hence carry same upwardly as the bit is removed. Pressure may be applied to the space 160a behind the sleeve 160 through conduit 16011 from any suitable source to press said sleeve against the string therein. Sleeve 160 not only prevents escape of circulating iluid but also prevents entrance of external water into the system.

In some installations, it is desirable to have a mud cross, indicated generally at 170. The cross may be of any Well known type and has conduit connections 172. The cross is adapted to function in the well known manner for example, the said cross may be used for relieving pressure or to kill the well should such action become necessary. A cross 170 is shown in FIG. l but is not included in the arrangement shown in FIGS. 4 and 5.

The assembly equipment also includes a flange sub 175 having a ange 176 having openings therein spaced annularly apart for reception of screws or bolts 177 4whereby said flange sub is attached to the lower end of the preventer 45. The flange sub is provided with the usual externally threaded pin, not shown, for attachment to the upper end of a safety joint barrel unit shown in FIGS. 1, 2 and 3 and hence will be given the same reference numeral, that is, reference numeral 32.

Means are provided whereby the assembled equipment may be guided by the guide cables 28 as said equipment is raised and lowered. This means includes arms connected to certain portions of the equipment and extending outwardly to slidably receive said guide cables adjacent the outer ends of said arms. More particularly, one pair of arms, indicated at 180, are formed integrally with the flange 176. These arms extend outwardly of the flange at diametrically opposite sides thereof and are provided with openings adjacent their free ends in which the guide cables 28 are slidably received. It is to be understood, of course, that the arms 180 may be otherwise secured to said flanges or may be otherwise attached to the assembly adjacent the lower ends thereof. At the upper end of the assembly, a pair of diametrically arranged arms 184 extend outwardly from funnel 47a and are provided adjacent their outer ends with respective openings for slidable reception of the guide cables 28. Thus, guide means are provided adjacent the top and bottom ends of the assembled equipment. It is to be understood, of course, that additional arms may be provided to connect other parts of the assembled equipment with said guide cables.

With the preventers 45 and 46, spool 135, and head 47 assembled into a unit said unit is lowered and connected to the mandrel 31. In order to support the unit while lowering same into position, a setting tool, indicated generally at 185 (FIG. l1), is used. This tool is elongated and has a rounded leading end 187. Adjacent the opposite end there is an external annular recess or groove 188. The tool 185 is connected to the lower end of a string as at 189 and said tool is inserted into the upper end of the assembled unit and positioned so that the groove 188 is engageable by the rams 147. The rams are closed on the tool and enter said groove so as to engage the inner reduced diameter portion 190 of tbe tool. The entire unit is then supported by the shoulder 191 at the lower end of groove 188 and the unit thus lowered with the Weight supported by said shoulder. It is to be understood, of course, that the arms 180 and 184 are connected to the guide cables 28 so that the unit is guided downwardly thereby. As the lower end of the tool 185 extends below the lower end of the barrel unit 32, said lower end of the tool serves as a guide which enters the bore of the mandrel and guides the safety joint barrel unit over said mandrel. While the cables 28 guide the above referred to unit of assembled equipment, the funnel 101 also functions as a guide should the lower end of the equipment unit become displaced for any reason out of alignment with respect to the mandrel. After the barrel unit 32 has been locked on the mandrel 31, the upper rarns 147 of the preventer 45 are actuated to the open position thereby releasing the tool 185 which is then raised along with the drill string to which it is attached.

The safety joint disclosed herein is similar to the kind taught by Waggener in United States Patent No. 2,893,- 694, having a reciprocated locking sleeve that prevents separation of the barrel and mandrel until said locking sleeve is retracted.

Following the removal of the blowout preventer setting tool, the drilling bit is asse-mbled on the drill collars with the rotating packer or sleeve of the head 47 stripped on directly above it. A bit guide is mounted above the packer and comprises a collar 200 comprising a pair of semicircular complementary parts which may be hinged at one side and secured at the other side by means of a latch or screw, not shown. The collar 200 is provided with an axial opening in which the drill pipe is slidably received and said opening is sutlciently large to permit passage therethrough of drill collars such as indicated at 201. The collar 200 is provided with outwardly extending arms '203 having openings adjacent their outer free ends for slidable reception of the guide cables 28. The bit with the guide disposed above it is then lowered, said bit entering the funnel 47a and passing downwardly through the head 47, spool 135, preventer 46, mud cross in the assembly shown in FIG. 1, preventer 45, and on down- Wardly through the safety release joint and into the casing 88.

As the bit enters the equipment unit, the rotating packer or seal 160 in the head 47 is seated therein and hydraulic pressure is applied to the pistons 163 to thereby lock said packer in place. If mud pump pressure is applied through the drill string at this time, it can be determined that the packer is correctly locked. The return of mud through the flow line 137 will indicate that the packer is correctly installed.

The cement may be drilled out and the well drilled in the conventional manner. The drilling bumper sub used during the preventer setting operation may be used during drilling operation to compensate for waves and tide motion.

In order to keep the guide cables 28 under proper tension, the torque converter of the unit 40 is set in the stall position, upward motion of the barge resulting in more lines automatically being spooled off the drum 34 while descending motion causes the line to be reeled in.

When the drilling bit becomes dull or it is desired to remove it from the hole, it is raised until in the area between the blind or complete shutoff rams 142 and the rotating packer. The rams are closed to prevent sea Water from entering the hole and the rotating packer or sleeve 160 is released by moving the segments 162 to the release position. The drill string may now be raised to the surface.

When the hole has been completed and it is necessary to remove the equipment unit, a special tool or gate lifting sub 210, FIG. 9, is used. The tool 210 is secured to the lower end of a bumper sub 62 which has its opposite end secured to a pipe string 189. The gate lifting sub is lowered until it touches the blind rams 142 which were closed prior to removal of the bit, said gate lifting sub 210 having an external annular recess or groove 212 therein which, when the lower end of said gate lifting sub rests on the blind rams, is located in the path of the pipe rams 147 which are closed to engage the reduced diameter portion 214 at the bottom of said recess 212.

Thereafter, the blind rams 147 are opened and a safety joint release tool 215, such as may be used for releasing a Waggener type safety tool joint, can then be inserted in the bore of the tubing on which the gate lifting sub is attached. Tool 215 has a head similar to the head 132 of the tool 130 and said head is adapted to seat on the shoulder 62a,in the upper part of the drilling bumper sub l62 which is directly above the gate lifting sub 210. This -releasing tool 215 extends downwardly below the gate lifting sub and adjacent the lower end is provided with fingers 216 similar to the lingers 133 of the releasing tool 130. When the bumper sub is substantially telescoped, the fingers 216 are positioned in the barrel unit of the safety joint so that when upward movement of the pipe string is effected with corresponding upward movement of the upper end of said bumper sub, the tool 215 will be raised and the fingers 216 will engage a shoulder within lthe key sleeve, not shown but substantially the same as that taught by Waggener in United States Patent No. 2,893,694, of the safety tool joint. Upon further upward movement of the pipe string, the bumper sub will be further extended and the key sleeve retracted to effectuate a release and allow the barrel and mandrel to be separated. Thereafter, when the bumper sub becomes fully extended, the equipment unit is raised to the surface, the shoulder 218 at the lower end of recess 212 of the gate lifting sub carrying the weight of the equipment unit as said unit is raised. Because the mandrel remains in place it will be apparent that should it be desired t reconnect the barrel to said mandrel, such reconnection may be effected.

After the drilling operation has been completed and the equipment unit raised, the cable and weight housing or anchor can be removed. A pull of adequate magnitude, such as five or six tons, for example, releases the anchor from the mandrel groove 115 so that the anchor may be raised to the surface.

In FIG. 16 an alternative type of submarine drilling head is disclosed. In this arrangement, there is a sleeve 225 to the outside of which is secured a collar 226 by means of a snap ring 227, said collar having an annular external recess 228. At the lower end of the sleeve 225 is a stripper rubber 230 of known character adapted to sealingly engage the string disposed therewithin. The sleeve 225 and the stripper rubber 230 are attached to the string in a manner similar to the attachment of the corresponding part above described in connection with the head 47. When the stripper rubber 230 and collar 225 are seated in the casing 232 of the head, pressure from a conduit 168 is supplied to the outer side of pistons 233 which are carried by plungers 234, the latter then being forced inwardly into the groove 228 to thereupon securely hold the sleeve 225 and rubber 230 in position. There are a plurality of annularly spaced plunger and piston devices and said plungers are |held inwardly by pressure supplied through the respective conduit 16'8. The plungers 234 are urged outwardly to release the sleeve 225 by pressure supplied by a respective conduit 168 to the opposite sides of said pistons 233. The plungers 234 are urged outwardly by respective springs 235 in a housing 236, said springs reacting against Washers 237 secured to the outer ends of the plungers by screws 238. Thus, should the pressure to the pistons 233 fail, the plungers 234 will be urged outwardly to effect release of the sleeve 225 so that the drill string may be removed.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description and it is thought that it will be apparent that various changes may be made in the form, construction, arrangement of the parts of the invention and steps of the method thereof, without departing from the spirit and scope of said invention or sacrificing all of its material advantages.

We claim:

1. In combination with a Well drilling string, apparatus for drilling a well in a formation under water, comprising: a floating support; means for anchoring said support; a casing positioned in said formation and having its upper end substantially at the surface thereof said casing being sealingly cemented in said formation; a safety release joint mandrel secured to the upper end of said casing; an anchor device releasably secured to said casing; flexible guides secured to and extending between said anchor device and said support; a vertical assembly of series connected drilling devices including a submarine head, a control gate having a gate ram and a safety release joint barrel unit, said unit Ibeing matable with said mandrel, said assembly defining a drill pipe passageway and said gate ram being operable into a position closing off said drill pipe passageway; means on said assembly for slidable engagement with said flexible guides; and means including connections and apparatus extending from said support for operating said submarine head and said control gate.

2. In combination with a well drilling string, apparatus for drilling a well in a formation under water, comprising: a floating support; means for anchoring said support; a casing positioned in said formation and having its upper end substantially at the surface thereof said casing being sealingly cemented in said formation; a safety release joint mandrel secured to the upper end of said casing; an anchor device releasably secured to said casing; flexible guides secured to and extending between said anchor device and said support; a vertical assembly of series connected drilling devices including a submarine head, a control gate having a gate ram, and a safety release joint barrel unit, said unit being matable with said mandrel, said assembly defining a drill pipe passageway and said gate ram being operable into a position closing olf said drill pipe passageway; means on said assembly for slidable engagement with said flexible guides; means including connections and apparatus extending from said support for operating said submarine head and said control gate; and means for lowering and raising said assembly from and to said support.

3. In combination with a well drilling string, apparatus for drilling a well in a formation under water, comprising: a floating support; means for anchoring said support; a casing positioned in said formation and having its upper end substantially at the surface thereof said casing being sealingly cemented in said formation; a safety release joint mandrel secured to the upper end of said casing; an anchor device releasably secured to said casing; flexible guides secured to and extending between said anchor device and said support; a vertical assembly of series connected drilling devices including a submarine head, a control gate having a gate ram, and a safety release joint barrel unit, said unit being matable with said mandrel, said assembly defining a drill pipe passageway and said gate ram being operable into a position closing olf said drill pipe passageway; means on said assembly for slidable engagement with said flexible guides; means including connections and apparatus extending from said support for operating said submarine head and control gate; and means engageable by a ram of said gate for supporting said assembly from said support.

4. In combination with a well drilling string, apparatus for drilling a well in a formation under water, comprising: a floating support; means for anchoring said support; a casting positioned in said formation and having its upper end substantially at the surface thereof, said casing being sealingly cemented in said formation; a safety release joint mandrel secured to the upper end of said casing; an anchor device releasably secured to said casing; guide cables secured to and extending between said anchor device and said support; means on said support for yieldingly maintaining said cables under tension; a vertical assembly of Series connected drilling devices including a submarine head, and a control gate having a gate ram, said assembly defining a drill pipe passageway and said gate ram being operable into a position closing olf said drill pipe passageway; a safety release joint barrel unit connected to the lowermost of said assembly devices and being matable with said mandrel; means on said assembly for slidable engagement with said cable; and means including connections and apparatus extending from said support for operating said submarine head and said control gate.

5. In combination with a well drilling string, apparatus for drilling a well in a formation under water, comprising: a oating support; means anchoring said support; a casing positioned in said formation and having its upper end substantially at the surface thereof, said casing being sealingly cemented in said formation; a safety release joint mandrel secured to the upper end of said casing; an anchor device releasably secured to said casing; guide cables secured to and extending between said anchor device and said support; means on said support for yieldably maintaining said cables under tension; a vertical assembly of series connected drilling devices including a submarine head, and a control gate having a gate ram, said assembly defining a drill pipe passageway and said gate ram being operable into a position closing off said drill pipe passageway; a safety release joint barrel unit connected to the lowermost of said assembly devices and being matable with said mandrel; means on said assembly for slidable engagement with said cable; means including connections and apparatus extending from said support for operating said submarine head and said control gate; and means for lowering and raising said assembly from and to said support.

6. In combination with a well drilling string, apparatus for drilling a well in a formation under water, comprising: a oating support; means anchoring said support; a casing positioned in said formation and having its upper end substantially at the surface thereof, said casing being sealingly cemented in said formation; a safety release joint mandrel secured to the upper end of said casing; an anchor device releasably secured to said casing; guide cables secured to and extending between said anchor device and said support; means on said support for yieldingly maintaining said cables under tension; a vertical assembly of series connected drilling devices including a submarine head, and a control gate having a gate rarn, said assembly defining a drill pipe passageway and said gate ram being operable into a position closing off said drill pipe passageway; a safety release joint barrel unit connected to the lowermost of said assembly devices and being matable with said mandrel; means on said assembly for slidable engagement with said cable; means including connections and apparatus extending from said support for operating said submarine head and said control gate; a pipe string projected from said support; and a setting tool for said assembly, said tool adapted for being connected to the projected end of said string and having an external recess for receiving a gate ram of a control gate.

7. In combination with a well drilling string, apparatus for drilling a well in a formation under water, comprising: a floating support; means anchoring said support; a casing positioned in said formation and having its upper end substantially at the surface thereof, said casing being sealingly cemented in said formation; a safety release joint mandrel secured to the upper end of said casing; an anchor device releasably secured to said casing; guide cables secured to and extending between said anchoring device and said support; means on said support for yieldingly maintaining said cables under tension;

a vertical assembly of series connected drilling devices including a submarine head, and a control gate having a ram, said assembly defining a drill pipe passageway and said gate ram being operable into a position closing olf said drill pipe passageway; a safety release joint barrel unit connected to the lowermost of said assembly devices and being matable with said mandrel; means on said assembly for slidable engagement with said cable; means including connections and apparatus extending from said support for operating said submarine head and control gate; a pipe string projected from said support; and a setting tool for supporting said assembly at the projected end of said string said tool including a body portion having an external recess for receiving a gate ram of a control gate and being of sufficient length to protrude outwardly from said barrel unit when engaged by said gate ram.

8. In combination with a well drilling string, apparatus for drilling a well in a formation under water, comprising: a floating support; means anchoring said support; a casing positioned in said formation and having its upper end substantially at the surface thereof said casing being sealingly cemented in said formation; a safety release joint mandrel secured to the upper end of said casing; an anchor device releasably secured to said casing; guide cables secured to and extending between said anchor device and said support; means on said support for yieldingly maintaining said cables under tension; a vertical assembly of series connected drilling devices including a submarine head, and a double cellar control gate having spaced upper and lower gate rams, said assembly defining a drill pipe passageway and said gate ram being operable into a position closing off said drill pipe passageway; a safety release joint barrel unit connected to the lowermost of said assembly devices and being matable with said mandrel; means on said assembly for slidable engagement with said cable; means including connections and apparatus extending from said support for operating said submarine head and control gate; a pipe string projected from said support and a lifting tool for supporting said assembly at the projected end of said string, said tool including a tubular body, said body having an external annular groove, the lower side of said groove being spaced from the leading end of said tool a distance equal to the spacing between the upper surface of said lower ram and the lower surface of said upper ram; whereby said groove will be positioned opposite the upper gate ram when said tool is fully projected into the upper end of said control gate and while said upper gate ram is opened and said lower gate ram is closed, said tool then engaging the upper surface of said lower rarn.

9. A lifting tool for a double cellar control gate having spaced upper and lower gate rams, said tool being adapted for connection to the end of a string and comprising: a body adapted to be passed into said gate, said body having a recess therein, the lower side of said recess being spaced from the leading end of said tool a distance equal to the spacing between the upper surface of said lower ram and the lower surface of said upper ram; whereby said recess will be positioned opposite the upper gate ram when said body is fully projected into the upper end of said control gate and while said upper gate ram is opened and said lower gate is closed, said tool then engaging the upper surface of said lower ram.

10. A lifting tool for a double cellar control gate having spaced upper and lower gate rams, said tool being adaptd for connction to the end of a string and comprising: a tubular body adapted to be passed into said gate, said body having an external annular groove the lower side of said groove being spaced from the leading end of said tool a distance equal to the spacing between the upper surface of said lower ram and the lower surface of said upper ram; whereby said groove will be positioned opposite the upper gate ram when said body is fully projected into the upper end of said control gate and while References Cited UNITED STATES PATENTS McNeill Z55-2.5 Bauer et al. Z55-2.5 Howard 166-47 Tucker Z55-2.5

14 2,891,770 v6/1959 Bauer et al. Z55- 2.5 X 2,912,214 11/ 1959 Allen et a1. 255-19 2,923,531 2/1960 Bauer et al. Z55- 2.5

CHARLES E. OCONNELL, Primary Examiner R. E. FAVREAU, Assistant Examiner U.S. C1. X.R. 175-7 

1. IN COMBINATION WITH A WELL DRILLING STRING, APPARATUS FOR DRILLING A WELL IN A FORMATION UNDER WATER, COMPRISING: A FLOATING SUPPORT; MEANS FOR ANCHORING SAID SUPPORT; A CASING POSITIONED IN SAID FORMATION AND HAVING ITS UPPER END SUBSTANTIALLY AT THE SURFACE THEREOF SAID CASING BEING SEALINGLY CEMENTED IN SAID FORMATION; A SAFETY RELEASE JOINT MANDREL SECURED TO THE UPPER END OF SAID CASING; AN ANCHOR DEVICE RELEASABLY SECURED TO SAID CASING; FLEXIBLE GUIDES SECURED TO AND EXTENDING BETWEEN SAID ANCHOR DEVICE AND SAID SUPPORT; A VERTICAL ASSEMBLY OF SERIES CONNECTED DRILLING DEVICES INCLUDING A SUBMARINE HEAD, A CONTROL GATE HAVING A GATE RAM AND A SAFETY RELEASE JOINT BARREL UNIT, SAID UNIT BEING MATABLE WITH SAID MANDREL, SAID ASSEMBLY DEFINING A DRILL PIPE PASSAGEWAY AND SAID GATE RAM BEING OPERABLE INTO A POSITION CLOSING OFF SAID DRILL PIPE PASSAGEWAY; MEANS ON SAID ASSEMBLY FOR SLIDABLE ENGAGEMENT WITH SAID FLEXIBLE GUIDES; AND MEANS INCLUDING CONNECTIONS AND APPARATUS EXTENDING FROM SAID SUPPORT FOR OPERATING SAID SUBMARINE HEAD AND SAID CONTROL GATE. 